(CN) – Former vice president and 2020 presidential hopeful Joe Biden has solidified his lead over the field of candidates for the Democratic nomination, restoring double-digit increases over his closest competitors in a Tuesday poll.
The CNN/SSRS poll of 1,001 Democratic and Democratic-leaning registered voters found 29 percent support the former vice president, a 7-point gain for Biden from a June survey.
The poll, conducted August 15-18, found 15 percent of potential voters support Vermont Sen. Bernie Sanders – an Independent seeking the Democratic nomination – while 14 percent back Massachusetts Sen. Elizabeth Warren.
Warren and Sanders’ respective positions in the poll have remained largely unchanged in summer polling by CNN.
California Sen. Kamala Harris saw a 12-point decline in the CNN poll, dropping from 17 percent support from potential voters in June to 5 percent support in Tuesday’s poll.
Harris’ current position in the poll mirrors her initial post-Democratic debate level of support following a standout performance in which she challenged Biden on school busing integration and his collaboration with conservative senators from southern states.
More self-identified Democrats (31 percent) than independents (23 percent) said they support Biden, according to Tuesday’s poll.
Biden has more support from voters aged 45 and up (34 percent) than from voters younger than 45 (23 percent), the poll found.
Support for Biden from moderate and conservative voters (34 percent) also outweighs backing from liberals, who split support in a near three-way tie between Warren at 23 percent and Biden and Sanders at 22 percent each.
Among liberals, 53 percent said beating President Donald Trump in the 2020 election is more important than selecting a candidate who “shares your positions on major issues,” while 57 percent of moderate or conservative Democratic voters said the same.
Of Democratic and Democratic-leaning registered voters, 54 percent said beating Trump in the 2020 election is the top priority and 35 percent of them also support Biden, the poll found.
No other Democratic candidate registers close to 5 percent support among liberals, the poll found.
Democratic candidate Julian Castro, the only Latino in the crowded field of 2020 candidates, registered 2 percent support in the CNN/SSRS poll Tuesday, reaching the polling threshold set by the Democratic National Committee to qualify for the September primary debate.